The Gene Targeting Core Facility (GTCF) is a fully established core resource to provide expert services for gene targeting of embryonic stem (ES) cells for the development of mouse models. The primary service orovided by this core is that of taking an investigator's gene targeting vector and producing ES cell lines that can be developed into chimeric mice that transmit the pertinent genomic modification(s) through their germline. Investigators utilizing this core have successfully produced a variety of gene knockouts and mouse models of disease. The GTCF is an integral component of the UAB Transgenic Mouse Facility that collectively provides expert services for not only gene targeting via the GTCF, but also blastocyst micro-injection of targeted ES cell clones or DNA constructs for the production of transgenic mouse models, as well as a host of services related to research with mice (e.g. cryopreservation of embryos, rederivation, etc.). The Transgenic Animal Facility is strategically linked with other core resources at UAB including the CCC Small Animal Imaging Core, Clinical Nutrition Research Center Small Animal Phenotyping Core, Research Animal Pathology Laboratory for phenotype assessment, and a specialized mouse-breeding core (Genetically Engineered Mouse and Marker-Assisted Genetics Core). Overall, we have premier resources to make and characterize mouse models for the Center investigators.